POM PT one step with a cross directional ripping-strip

ABSTRACT

A bag comprising adhesive material applied on a ply step of the bag, a ripping-strip and a non adhesive coated area embedding the ripping-strip, providing an easy opening feature at the customer open end of the bag. The bottom of the bag comprises a folded flat bottom. The bag preferably holds an inserted inner bag. The bag has a top closure that can be folded above a customer seal in order for the inner bag to be fully independent from the outer bag after the bag is opened with the help of a ripping-strip. Upon closure of the bag, the inner bag is not trapped in an upper flap of the outer bag in order for the bag to be fully recyclable. Preferably, a mid-step is provided with the mid ply of the outer bag. The mid step stiffens and reinforces the flap.

FIELD OF THE INVENTION

The present invention relates generally to the field of the paper bag industry and more particularly to the production of a Paste Open Mouth (POM) style bag with a Pinched Top (PT), embracing an inserted inner bag, as well as a method of closing such a bag.

BACKGROUND

In the paper bag industry, so far, nobody has been able to provide an easy and secure opening feature in a POM style bag with a pinched top (PT) in a 2 or 3 paper ply bag with a poly inserted inner bag.

On the known version of POM PT style bags, the bottom is covered with a patch. Customers require a special sealer which cuts the inner bag just above the seal to prevent the inner bag from being caught in the flap at the top closure. The access to the inner bag is thus difficult. Even when an easy opening feature is implemented, the end user usually uses a knife to open the bag, resulting in potential damage to the bag and risk of injury.

The Sewn Open Mouth (SOM) liner, the most traditional bag, offers easy access to the liner or inner bag. During manufacturing, the liner is manually inserted and sealed. The bag is closed with the help of a sewing thread. The manufacturing process is labour intensive, has a high lead time and creates risk of injury during the manual insertion. The final product has a poor standing-ability, exhibits a high risk of contamination during the filling process and is not compatible with the PT closing equipment.

The Self-Opening-Style (SOS) liner is very similar to the SOM liner. However, it stands better on a flat surface. It still exhibits similar limitations of the SOM liner.

The SOS PT bag (or commercially known as a “WEBB bag”) is a very expensive bag and is only offered by a limited amount of suppliers. It has a square bottom and is compatible with the pinch closure equipment on the top. The bag provides a good pallet display, but still has limitations. The inner bag cannot be separated from the paper bag and hence both cannot be recycled. It is also not possible to seal the liner fully hermetically.

A very popular version in industry is the Pinch Bottom Open Mouth (PBOM) bag. Its top closure is pinch type and is therefor adapted to the same closing equipment. Again the inner bag cannot be separated and it has a poor standing-ability.

Other types of multi-wall bags are described in the following family of patents: U.S. Pat. Nos. 3,807,626; 3,910,488 and 3,958,749 (all GOODRICH) which all disclose a gusseted pinch bottom breakaway pouch bag. These documents specify that the bags have an innermost bag ply of a heat sealable plastic material. In the process of bag manufacture on a bag tuber, the innermost bag ply is only loosely adhered to the contiguous outer paper ply for manual detachment therefrom and is heat sealed transversely, through the outer bag at the closed end, by heat sealing between pressure bars. The bag closure at the closed end is otherwise completed by folding over an overlapping wall portion of the outermost plies and sealing against the outer wall. Also, when the bag is filled with a comestible or the like, the opposite end of the plastic ply is closed by heat sealing as well as by heating a thermoplastic adhesive prior to folding over and sealing the overlapping wall portions H of the outermost plies at the end. The plastic ply is of such length as not to be included in the sealed bag end closures provided by the outermost plies. The bag may thus be opened in the outermost plies leaving intact the plastic ply and therein the packaged contents. Since the plastic ply is only lightly adhered to the contiguous ply, the outer plies may be torn or cut away and peeled off of the plastic ply without rupture thereof for removal of a thus completely sealed and impervious plastic ply container of the packaged material. These documents further disclose that the bag can be opened by pulling on a tear cord.

Unfortunately, the GOODRICH-type bag must be filled upside down in order to get the easy open at the top afterwards. This type of bag is not very stable in upright positions, especially in very large formats. The tear cord is located on the bottom (closed) end and not at the customer top end which is usually sealed by the customer. The cord type easy opening feature could not be applied on the customer end as it is too long and non rigid. Since the ends of the cord could easily be trapped in the flap when closed by the customer, the end user might not have any access to the cord ends in order to open the bag.

Similarly, U.S. Pat. No. 5,007,233 (BOSE) teaches a multi-wall bag including an outer paper bag and one or more inner thermoplastic bags that are ultrasonically sealed closed. The open end of the paper bag is closed and folded back on itself with a small amount of adhesive being applied to keep the paper bag closed. Once again, the paper bag can easily be opened and the thermoplastic bag can be removed therefrom. However, once again, this type of bag does not have a flat bottom and is not stable in an upright position.

U.S. Pat. No. 6,536,190 (WEBB) discloses a multi-wall sack having an inner bag and an outer bag which encloses the inner bag and has block ends. Similarly to POM PT bags described above, the easy open feature on this bag is located within the patch (or label) at the end of the bag. This easy open feature is not very efficient as many steps are required to open the bag. Consequently, customers very often use a knife to rip open the bag. This method of opening is hazardous, with risk of injury to the customer or damage to the inner bag. This in turn may result in a loss of product which can be costly in cases where the product being carried in the bag is expensive.

Several other prior art documents describe various types of multi-wall bags and methods of closing these bags. These documents are known to the Applicant by the following patent numbers: U.S. Pat. No. 3,929,275 (BOLLING et al.); U.S. Pat. No. 4,110,953 (HOLMES); U.S. Pat. No. 4,210,249 (HOLMES); U.S. Pat. No. 4,353,770 (KUCKHERMANN); U.S. Pat. No. 4,557,385 (ROBINSON); U.S. Pat. No. 4,840,611 (VAN ERDEN et al.); U.S. Pat. No. 5,007,233 (BOSE); U.S. Pat. No. 5,338,117 (KUCKSDORF et al.); U.S. Pat. No. 5,365,720 (BUNCH); and U.S. Pat. No. 6,168,312 (HAUSSLEIN).

An easy opening feature at the customer open end of bags is yet to be seen in the prior art. It is very difficult to apply an easy open feature at the customer end. There is thus still a need for a POM PT bag having an easy open feature at the customer end.

SUMMARY OF THE INVENTION

An object of the invention is to provide a POM PT bag that satisfies the above-mentioned need.

According to the present invention, that object is achieved with a bag comprising:

-   -   an open top end;     -   a closed bottom end;     -   a first wall portion;     -   a second wall portion opposite the first wall portion;     -   an upper flap on the first wall portion extending above a top         edge of the second wall portion, and being foldable against the         second wall portion, the upper flap having two opposite side         edges;     -   an adhesive along the upper flap for closure of the upper flap         against the second wall portion after being folded; and     -   a ripping strip extending along the upper flap in an area         between a location above the top edge of the second wall portion         and the adhesive.

Preferably, the bag according to the present invention comprises an inner bag of heat sealable plastic material removably attached to the above-mentioned bag, hereinafter referred to as an outer bag, comprising:

-   -   a closed bottom end removably bonded on an inside surface of the         outer bag adjacent the closed bottom end of the outer bag; and     -   an open top end removably bonded on the inside surface of the         outer bag adjacent the open top end of the outer bag, the inner         bag being sized such that a top edge thereof extends at a same         level with or below the top edge of the second wall portion of         the outer bag.

Preferably, the ripping strip has at least one end exceeding one of said side edges of the flap.

As can be appreciated, the bag according to the present invention has an easy-open feature at the customer end of the bag.

Another object of the invention is to provide such a POM PT bag having an inserted liner or inner bag. Preferably, the inner bag is made of polyethylene. In another embodiment of the present invention, the inner bag may be omitted.

Preferably, the outer bag is made of multiple-ply paper. In another embodiment of the present invention, the outer bag is made of a single ply paper sufficiently strong to hold the contents of the bag.

Preferably, the outer bag comprises an inner ply, a mid ply and an outer ply. The upper flap is formed by upper extensions of the outer ply and the mid ply. The upper extension of the outer ply is longer than the upper extension of the inner ply. In another embodiment of the present invention, the outer bag and upper flap comprise additional plies, depending on the design requirements of the bag.

Another object of the invention is to provide such a POM PT bag having a top closure that can be folded above a customer seal in order for an inner liner or inner bag to be fully independent from the outer bag after the bag is opened with the help of a ripping-strip (easy opening feature). Preferably, frangible dotted lines or slits are provided on either side of the ripping strip and in proximity thereof to facilitate the opening of the bag. Preferably, in the case of paper bags, at least one of the side edges of the upper flap is provided with a slit on either side of the ripping strip in proximity thereof to facilitate the ripping of the upper flap. As mentioned above, according to a preferred embodiment, the ripping strip has at least one end exceeding one of said side edges of the flap. According to another preferred embodiment, the ripping strip does not exceed one of the said side edges of the flap. Access to the ripping strip in this configuration is made possible by providing slits on either side of the ripping strip, thereby allowing the ripping strip to be lifted and pulled to open the bag.

Another object of the invention is to provide such a POM PT bag wherein the inner bag is not trapped in an upper flap of the outer bag in order for the bag to be fully recyclable.

Another object of the invention is to provide such a POM PT bag in which an inner bag can be removed from the bag for hygienic reasons (as for the food and pharmaceutical industries).

Another object of the invention is to provide a POM PT bag comprising an adhesive material applied on a ply step of the bag, a ripping-strip and a non adhesive coated area embedding the ripping-strip. Preferably, the adhesive is hot met glue. In another preferred embodiment, the adhesive is a two-face adhesive tape.

Preferably, the bottom of the bag also comprises a folded flat bottom.

Another object of the present invention is to provide a method of closing a bag including an inner bag, according to the present invention, comprising the following steps at the completion of filling a product into the bag through the open top ends of the inner and outer bags:

-   -   (a) sealing the inner bag through the outer bag to form a         customer seal which closes the inner bag; and     -   (b) folding the upper flap against the second wall portion of         the outer bag.

Preferably, when the adhesive on the ply step is a hot melt glue, the method further comprises, between step (a) and step (b), a step of heating the adhesive.

Preferably, step (a) of sealing of the method according to the present invention comprises the step of heating the inner bag through the outer bag with heating elements.

Another object of the present invention is to provide a bag comprising:

-   -   an outer bag comprising:         -   an open top end         -   a closed bottom end;         -   a first wall portion,         -   a second wall portion opposite the first wall portion;         -   an upper flap on the first wall portion extending above a             top edge of the second wall portion, and being foldable             against the second wall portion, the upper flap having two             opposite side edges;         -   an adhesive along the upper flap for closure of the upper             flap against the second wall portion after being folded; and         -   a ripping strip extending along the upper flap in an area             between a location above the top edge of the second wall             portion and the adhesive; the ripping strip having at least             one end exceeding one of said side edges of the flap; and     -   an inner bag of heat sealable plastic material removably         attached to the outer bag, comprising:         -   a closed bottom end removably bonded on an inside surface of             the outer bag adjacent the closed bottom end of the outer             bag; and         -   an open top end removably bonded on the inside surface of             the outer bag adjacent the open top end of the outer bag,             the inner bag being sized such that a top edge thereof             extends at a same level with or below the top edge of the             second wall portion of the outer bag.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the invention will become apparent upon reading the detailed description and upon referring to the drawings in which:

FIG. 1 is a perspective front view of a top portion of a POM PT bag according to a preferred embodiment of the present invention, with an upper portion of the second wall portion of the outer bag broken away to show the inner bag;

FIG. 2 is another perspective front view of the top portion of the POM PT bag of FIG. 1, with the flap folded against the second wall portion;

FIG. 3 is another perspective front view of the POM PT bag of FIG. 1 showing the top and the bottom closures.

FIG. 4 is a perspective front view of the bottom portion of the POM PT bag of FIG. 1, showing the bottom enclosure partially opened.

FIG. 5 is a perspective front view of a POM PT bag according to another preferred embodiment which includes a mid-step with the mid ply.

FIG. 6 is a perspective front view of the top portion of the POM PT bag of FIG. 5 including a mid-step with the mid ply.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Referring to FIGS. 1 to 6, there is shown a POM PT style paper bag having an outer ply 1. The number of plies can varies through the field of application and the bag is preferably made of paper. The bag comprises a pasted open mouth and has a pinched top closure. The bag has a flat bottom closure in order for the bag to stand in an upright position on a flat surface such as a conveyor and to stack better when compared, for example, to PBOM-type bags. The filled bag preferably has a triangular profile converging from the bottom closure to a top closure of the bag when in standing position.

More specifically, the bag according to the present invention comprises an outer bag 20. Preferably, the bag according to the present invention further comprises an inner bag 3. In another embodiment of the present invention, the inner bag 3 may be omitted.

The outer bag 20 comprises an open top end 22 and a closed bottom end 2. The outer bag 20 further comprises a first wall portion 24 and a second wall portion 26 opposite the first wall portion 24. Moreover, the outer bag 20 comprises an upper flap 10 on the first wall portion 24 extending above a top edge 34 of the second wall portion 26. The upper flap is foldable against the second wall portion 26, and has two opposite side edges. Furthermore, the outer bag 20 comprises an adhesive 6 along the upper flap 10 for closure of the upper flap 10 against the second wall portion 26 after being folded. The outer bag 20 further comprises a ripping strip 8 extending along the upper flap 10 in an area 7 between a location above the top edge 34 of the second wall portion 26 and the adhesive 6. The ripping strip 8 has at least one end exceeding one of the side edges of the flap 10. According to another preferred embodiment, the ripping strip 8 does not exceed one of the side edges of the flap. Access to the ripping strip 8 in this other configuration is made possible by providing slits on either side of the ripping strip 8, thereby allowing the ripping strip 8 to be lifted and pulled to open the bag.

The inner bag 3 is made of heat sealable plastic material and is removably attached to the outer bag 20. The inner bag 3 comprises a closed bottom end 30 removably bonded on an inside surface of the outer bag 20 adjacent the closed bottom end 2 of the outer bag 20. The inner bag 3 further comprises an open top end 28 removably bonded on the inside surface of the outer bag 20 adjacent the open top end 22 of the outer bag 20. The inner bag 3 is sized such that a top edge 32 thereof extends at a same level with or below the top edge 34 of the second wall portion 26 of the outer bag 20.

As mentioned above the top closure 12 of the bag has an upper flap 10 that can be folded, along a guideline axis 5, on the outer ply 1 for closing the open mouth. The adhesive is preferably a coated adhesive 6 located on the upper flap 10. Preferably, the coated adhesive 6 applied on the upper flap 10 is a strip of hot melt glue. The hot melt glue has to be reactivated before closure of the bag to ensure a tight seal. Other adhesive coating material, or tape, can also be used for the same purpose. For example, a two-face adhesive tape can be applied on the upper flap 10. An advantage of the adhesive tape over the hot melted glue is that it does not require from a user to have a special closing equipment to close the bag. A soluble glue can also be used to facilitate recycling of the paper bag.

The ripping-strip 8 is located within an area 7. The area 7 is located between the adhesive coating material 6 on the upper flap 10 and the open mouth of the bag. This area 7 is kept free of adhesive material and hence forms a non-coated area 7. The ripping-strip 8 can be made of any synthetic material. For easy gripping by a user, the ripping-strip 8 has a portion 11 exceeding an edge of the bag. This portion 11 of the ripping-strip 8 provides adequate length for the customer to get hold of it. The bag preferably has frangible dotted lines 9 (or alternately slits) on both sides along the ripping-strip 8 to further ease the opening process. The ripping-strip 8 is preferably cut at the width of the paper bag. The ripping strip is preferably made of tape which is pre-glued (self adhesive) and this tape could be applied by pressure or with a combination of heat and pressure.

The inner bag 3 is inserted within the bag. The inner bag 3 is preferably made of polyethylene. The open mouth of the inner bag 3 is located near the open mouth of the outer bag.

During the manufacturing process of the bag, the inner bag 3 is mechanically inserted into the outer bag in the form of a continuous poly tubing. The bottom of this poly tubing is heat sealed during the manufacturing process. As shown in FIG. 4, glue points between the bag and the inner bag 3 secure the bottom of the inner bag 3, including the seal 14, to the interior bottom of the outer bag 20. The inner bag 3 can be completely removed from the bag after the pinched top closure is ripped open by the ripping-strip 8.

At a user's filling facility, for example, a product is filled in the inner bag 3. Then, using a conventional sealer, the inner bag 3 is sealed through the paper bag to form the customer seal 4. The adhesive coating material 6 is heated and the upper flap 10 is folded just above the customer seal 4 of the inner bag.

Consequently, another object of the present invention is to provide a method of closing a bag including an inner bag, comprising the following steps at the completion of filling a product into the bag through the open top ends of the inner and outer bags:

-   -   (a) sealing the inner bag 3 through the outer bag 10 to form a         customer seal which closes the inner bag 3; and     -   (b) folding the upper flap 10 against the second wall portion 26         of the outer bag 20.

The sealing of the open mouth of the inner bag 3 is preferably done by heating elements heating the inner bag 3 through the paper bag. The heat is transferred to the inner bag 3 which seals itself. It is important to note that during the sealing process, the inner bag 3 does not react with the paper bag and does not adhere to it. To remove the inner bag 3 once the upper flap 10 is folded and sealed on the outer ply 1, the user has to grab the ripping-strip 8 by the exceeding portion 11 and tear it off. Then, the user can remove the inner bag 3 from the outer bag or leave it there. This is a bag in a bag concept.

It is recommended to use high performance paper in order to provide a strong flap at the closure. As shown in FIGS. 5 and 6, it is also possible to position a mid-step with the mid ply 40 in a 3 paper ply bag design. The mid-step is designed in such a way that the inner bag would still be positioned above the folding line 5. This mid step 40 can stiffen and reinforce the flap 10. In another preferred embodiment, more steps may be provided.

More specifically, the outer bag 20 preferably comprises an inner ply, a mid ply 40 and an outer ply 42. The upper flap 10 is formed by upper extensions of the outer ply 42 and the mid ply 40. The upper extension 44 of the outer ply 42 is longer than the upper extension 46 of the mid ply 40.

The bag is also compatible with a sealing head where the inner bag is trimmed just above the seal. The stepping pattern could be traditional or the one step as described in this patent.

In the case of a three paper ply bag, the mid ply could be stepped at mid position of the outer ply step. In this case it could be possible to add two slits at the start to help the opening.

The POM PT style bag of the present invention has the following advantages:

-   -   Easy access to the inner bag 3 (poly tubing), easy, secure and         fast opening;     -   The paper bag and the poly bag are recyclable;     -   Compatible with a conventional sealer where the inner bag is         heat sealed through the paper bag at the top. The conventional         sealer cannot cut the inner bag above the seal;     -   This bag style offers a good pallet display;     -   Stands very well on conveyors or on the floor;     -   Minimum labour required for the filling process;     -   Very hygienic bag as there is a minimal handling. The bag and         the process were designed in order to minimize the potential         product contamination. This bag is compatible with the actual         requirements of the food industry;     -   The closing is strong and secure from a food safety perspective;         and     -   The bag is compatible with existing automatic bag feeders.

The POM PT bag can be made of the following materials:

-   -   Inner bag 3: Poly tubing (should be strong enough to carry the         material by itself);     -   Inner ply of the paper bag: Multi-wall kraft paper (high         performance paper is recommended);     -   Mid ply of the paper bag (optional): Multi-wall kraft paper         (high performance paper is recommended);     -   Outer ply of the paper bag: Multi-wall kraft paper (printed or         plain; high performance paper is recommended); and     -   Closure components: Hot melt glue (regular or soluble) or two         sided auto-adhesive tape, ripping-strip made of synthetic         material.

While embodiments of this invention have been illustrated in the accompanying drawings and described above, it will be evident to those skilled in the art that changes and modifications may be made therein without departing from the essence of this invention. 

1. A bag comprising: an open top end; a closed bottom end; a first wall portion; a second wall portion opposite the first wall portion; an upper flap on the first wall portion extending above a top edge of the second wall portion, and being foldable against the second wall portion, the upper flap having two opposite side edges; an adhesive along the upper flap for closure of the upper flap against the second wall portion after being folded; and a ripping strip extending along the upper flap in an area between a location above the top edge of the second wall portion and the adhesive.
 2. A bag according to claim 1, comprising: an inner bag of heat sealable plastic material removably attached to said bag, hereinafter referred to as an outer bag, comprising: a closed bottom end removably bonded on an inside surface of the outer bag adjacent the closed bottom end of the outer bag; and an open top end removably bonded on the inside surface of the outer bag adjacent the open top end of the outer bag, the inner bag being sized such that a top edge thereof extends at a same level with or below the top edge of the second wall portion of the outer bag.
 3. A bag according to claim 1, wherein the ripping strip has at least one end exceeding one of said side edges of the flap.
 4. A bag according to claim 1, wherein the adhesive is a strip of hot melt glue.
 5. A bag according to claim 1, wherein the adhesive is a two-face adhesive tape.
 6. A bag according to claim 1, wherein the upper flap has frangible dotted lines on either side of the ripping strip and in proximity thereof to facilitate the ripping of the upper flap.
 7. A bag according to claim 1, wherein at least one of the side edges of the upper flap is provided with a slit on either side of the ripping strip in proximity thereof to facilitate the ripping of the upper flap.
 8. A bag according to claim 2, wherein the outer bag is made of paper.
 9. A bag according to claim 2, wherein the outer bag is made of multiple plies.
 10. A bag according to claim 9, wherein the outer bag comprises an inner ply, a mid ply and an outer ply, and wherein the upper flap is formed by upper extensions of the outer ply and the mid ply.
 11. A bag according to claim 10, wherein the upper extension of the outer ply is longer than the upper extension of the mid ply.
 12. A bag according to claim 2, wherein the inner bag is made of polyethylene.
 13. A bag according to claim 1, wherein the closed bottom end of the outer bag is a flat bottom.
 14. A method of closing a bag according to claim 2, comprising the following steps at the completion of filling a product into the bag through the open top ends of the inner and outer bags: (a) sealing the inner bag through the outer bag to form a customer seal which closes the inner bag; and (b) folding the upper flap against the second wall portion of the outer bag.
 15. The method according to claim 14, wherein the adhesive is a hot melt glue and the method further comprises, between step (a) and step (b), a step of heating the adhesive.
 16. The method according to claim 14, wherein step (a) of sealing comprises the step of heating the inner bag through the outer bag with heating elements.
 17. A bag comprising: an outer bag comprising: an open top end a closed bottom end; a first wall portion, a second wall portion opposite the first wall portion; an upper flap on the first wall portion extending above a top edge of the second wall portion, and being foldable against the second wall portion, the upper flap having two opposite side edges; an adhesive along the upper flap for closure of the upper flap against the second wall portion after being folded; and a ripping strip extending along the upper flap in an area between a location above the top edge of the second wall portion and the adhesive; the ripping strip having at least one end exceeding one of said side edges of the flap; and an inner bag of heat sealable plastic material removably attached to the outer bag, comprising: a closed bottom end removably bonded on an inside surface of the outer bag adjacent the closed bottom end of the outer bag; and an open top end removably bonded on the inside surface of the outer bag adjacent the open top end of the outer bag, the inner bag being sized such that a top edge thereof extends at a same level with or below the top edge of the second wall portion of the outer bag. 